   .sidebar {
       width: 250px;
       background-color: #2c3e50;
       height: 100vh;
       position: fixed;
       top: 0;
       left: 0;
       padding: 20px;
       box-shadow: 2px 0 8px rgba(0, 0, 0, 0.1);
   }
   .sidebar h3 {
       color: #ffffff;
       font-weight: 600;
       margin-bottom: 20px;
       text-align: center;
   }
   .sidebar ul {
       list-style: none;
       padding: 0;
   }
   .sidebar ul li {
       margin-bottom: 10px;
   }
   .sidebar ul li a {
       color: #bdc3c7;
       text-decoration: none;
       font-size: 16px;
       display: block;
       padding: 10px;
       border-radius: 4px;
       transition: background-color 0.3s, color 0.3s;
   }
   .sidebar ul li a:hover {
       background-color: #34495e;
       color: #ffffff;
   }
   .sidebar ul li a.active {
       background-color: #007bff;
       color: #ffffff;
   }

   /* 主内容区域样式 */
   .main-content {
       margin-left: 270px; /* 留出导航栏空间 */
       padding: 20px;
   }
   .help-item {
       background-color: #f8f9fa;
       padding: 20px;
       border-radius: 8px;
       margin-bottom: 20px;
       border-left: 4px solid #007bff;
       transition: background-color 0.3s, box-shadow 0.3s;
   }
   .help-item:hover {
       background-color: #e9ecef;
       box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
   }
   .help-item h5 {
       margin-bottom: 10px;
       font-weight: 600;
       color: #2c3e50;
   }
   .help-item a {
       text-decoration: none;
       color: #007bff;
       font-weight: 500;
   }
   .help-item a:hover {
       text-decoration: underline;
   }
   .help-item p {
       line-height: 1.6;
       color: #4a4a4a;
   }
   .help-item h6 {
       margin-top: 15px;
       margin-bottom: 10px;
       font-weight: 600;
       color: #34495e;
   }